Quote by Bertrand Meyer

“Worse yet is the rejection of upfront requirements. The basic observation is correct: requirements will change, and are hard anyway to capture at the beginning. In no way, however, does it imply the dramatic conclusion that upfront requirements are useless! What it does imply is that requirements should be subject to change, like all other artifacts on the software process. [...] The agile advice here is irresponsible and serious software projects should ignore it.The sound practice is to start collecting requirements at the beginning, produce a provisional version prior to engaging in design, and treat the requirements as a living product that undergoes constant adaptation throughout the project.”

Quote by Bertrand Meyer